Subscapularis

This is the last of the rotator cuff muscles and it’s the largest and strongest.

Where is it?

This one is tough to get your hand on because of the fact that it is underneath the scapula

Subscap behind our rib cage

(hence the name) and you can’t really get at it from the front because of the rib cage.

If however you put your right hand behind your back then take your left hand around your back and try to dig your fingers underneath the medial border of the scapula you can get at the origin of this muscle. In this position you can palpate them through the trapezius and rhomboids that lie over top.

Right Subscapularis - view from the back and front (minus the rib cage)

What Does It Do?

It is the largest muscle of the rotator cuff allowing it to create 1725 N of internal rotation force at 90 degrees and 1297 at 0 degrees of abduction (Decker et al. 2003). However at zero degrees of abduction the pectoralis major, latissmus dorsi and teres major all assist in creating internal rotation while the 90 degree version didn’t recruit these bigger muscles allowing you to isolate the subscapularis.

During the throwing motion the subscapularis help depress the humeral head to prevent injury but it also contributes to the act of throwing by providing some internal rotation power for when your arm starts to rotate to deliver the ball.

What Are the Best Exercises?

The most popular exercises you will see are standing internal rotation exercises with the

Internal Rotation at Zero Degrees of Abduction

arm either tucked at the side or at 90 degrees in the field goal position.

As mentioned above the 90 degree version has the benefit of not have bigger muscles like the pecs and lats take over allowing you to target the subscapularis specifically but it this position isn’t as stable compared to when your arm is tucked in at your side.

Internal Rotation at 90 degrees of abduction

There are some other exercises that aren’t your typical “rotator cuff” exercises that have

Arms straight - sink & extend

been shown to promote some high activation from the subscapularis. The pushup plus which is most regarded as a serratus anterior exercise recruits the subscap and so does the band bear hug which is essentially the same motion as the pushup plus but with a band. (Decker et al. 2003)

Band Bear Hug - perform like a fly motion - pic from Reinold (2009)

There are some “new” exercises that have you training the subscapularis in a diagonal motion with your shoulder abducted which offers up the ability to train in a “functional pattern.”

"Functional" subscap training - Reinold et al. (2009)

Bottom Line

All of these exercises are great plus it nice to mix things up so you aren’t the same exercise every day.

Of the rotator cuff muscles it is the least likely to be weak due to its size and the fact that it gets used every time you throw – ensure that you hit the other rotator cuff muscles prior to attacking the subscapularis.

Be sure to check out the next article which will look at other areas of the body and shoulder that need to be addressed in order to promote shoulder healthy and performance.